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MWM Bins are here


Marvel

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Eldon get's the first prize. Wired for one 15 from each side. Sounds pretty nice that way. At least that's safe for my Moondogs. I'll leave it that way for awhile. I'll be picking hp a Crown xli800 before december. I know that will work.

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I have the SNs...they are right above the terminal strips.

 

What gets me is the cut sheet for these says the K43 woofers are 8 ohm, which would make the inicated impedance 4 ohms correct

 

 

20190819_173348.jpg

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@glens   I will repeat... The literature says the K43 is 8 ohms, but in fact, they are 4 ohms. At least the DCR is about 3.9 each. Everyone has commented before that they are 4 ohms each. Default wiring is parallel, so the label should say 2 ohms. I could replace all 4 with 8 ohm drivers (don't want to spring for that).

 

The chamber for each does open from one to the other. Although I have connected one driver to each amp channel and it is pretty nice sounding. I would like the gain from the second woofer, of course.

 

 

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3 hours ago, Marvel said:

'll be picking hp a Crown xli800 before december. I know that will work.

Great to read about you getting these MWM's. ONE of those Crown xli800's was enough to run my three way stacks with OEM crossovers louder than I could listen to without hearing protection.

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29 minutes ago, Marvel said:

@glens   I will repeat... The literature says the K43 is 8 ohms, but in fact, they are 4 ohms. At least the DCR is about 3.9 each. Everyone has commented before that they are 4 ohms each. Default wiring is parallel, so the label should say 2 ohms. I could replace all 4 with 8 ohm drivers (don't want to spring for that).

 

The chamber for each does open from one to the other. Although I have connected one driver to each amp channel and it is pretty nice sounding. I would like the gain from the second woofer, of course.

 

 

3.9 ohms DCR indicates about a 6 ohm impedance using frequency sweeps, So it looks like about 3 ohms in parallel. Most pro amps can drive this, especially in a home environment where you are NOT likely to use more than a watt or two. Also, since the inputs are separate, why not just wire them in series if you are concerned? What's the big deal?

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37 minutes ago, Marvel said:

The chamber for each does open from one to the other.

I thought they were separated, one layer of wood between the top horn and bottom horn all the way to the back ? Like two singles with one less layer between two cabinets ?

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They are joined where the notches are cut on the corners.

1 hour ago, ClaudeJ1 said:

3.9 ohms DCR indicates about a 6 ohm impedance using frequency sweeps, So it looks like about 3 ohms in parallel. Most pro amps can drive this, especially in a home environment where you are NOT likely to use more than a watt or two. Also, since the inputs are separate, why not just wire them in series if you are concerned? What's the big deal?

 

I did try them in series. At the moment I'm using the passives from my LS and at 8 ohm the balance is a little off. I'm currently using

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2 hours ago, Marvel said:

@glens   I will repeat... The literature says the K43 is 8 ohms, but in fact, they are 4 ohms. At least the DCR is about 3.9 each. Everyone has commented before that they are 4 ohms each. Default wiring is parallel, so the label should say 2 ohms. I could replace all 4 with 8 ohm drivers (don't want to spring for that).

 

The chamber for each does open from one to the other. Although I have connected one driver to each amp channel and it is pretty nice sounding. I would like the gain from the second woofer, of course.

 

 

 

Now remember, the DC resistance is only about 2/3rds to 3/4ths of the drivers impedance and the horn adds 50% to 75% more impedance.  A K-33 has a DCR of 3.2 ohms, is considered 4 ohms nominal and runs an actual 6.4 ish ohms in a La Scala bass horn.  I'm sure it rises as frequency rises above 400 Hz. 

 

If you haven't, check the DCR of each (I didn't see where you said you did).  Then, you can safely double it for total impedance in a horn. 

 

Four ohms with both woofers in parallel is a very fair number. 

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14 hours ago, Marvel said:

John Albright, who designed the DHA2 crossovers I built, said I could replace the 2.5mH inductor on the woofer with a lower value to raise the woofer crossover point back up to 400Hz.

 

Plus, I'm not sure how well my 2a3 amps would deal with the current. I could swap in the Duke to try it.

 

Might try Eldon's idea of connecting a single woofer to it first.

Without curves or an existing crossover schematic to extrapolate from, it's a swag. 

 

Use a 1.25mH, terminate the rest of the network with resistors, and measure. 

 

I don't know how your 2a3 amps would do with this. 

 

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10 hours ago, JohnA said:

A K-33 has a DCR of 3.2 ohms

 

I remeasured  one of the K43s this a.m. and got close... between 3.2 to 3.4.

 

2 hours ago, Deang said:

I don't know how your 2a3 amps would do with this. 

 

That is what has me a bit worried.  They are wired for 8 ohms and I would have to open them up to rewire the outputs for 4 and I'm not wanting to do that. I'm getting a Crown XLI800 to use for some pa work, so I will wait to try it with that. Right now it sounds really clean with the 2A3 amps using only one per side (like an MWM-S).

 

10 hours ago, JohnA said:

A K-33 has a DCR of 3.2 ohms, is considered 4 ohms nominal and runs an actual 6.4 ish ohms in a La Scala bass horn.

 

Will they rise that much in the MWM? The throat is much larger, so there isn't as much compression going on.

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Here's the old pdf of the MCM1900 system. Note on page two, each cabinet has two K-43 drivers at a nominal 8 ohms each. Now they are 4 ohm drivers. That is what I was getting at earlier. Those at 8 ohms each in parallel wouldn't be a problem for me.

 

Somewhere along the line they must have changed them.

 

MCM1900good.pdf

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Ye of little faith!  Don't split hairs between nominal and actual impedance. And don't look at DCR as actual impedance. 

 

14 hours ago, Marvel said:

 

I remeasured  one of the K43s this a.m. and got close... between 3.2 to 3.4.

 

 

That is what has me a bit worried.  They are wired for 8 ohms and I would have to open them up to rewire the outputs for 4 and I'm not wanting to do that. I'm getting a Crown XLI800 to use for some pa work, so I will wait to try it with that. Right now it sounds really clean with the 2A3 amps using only one per side (like an MWM-S).

 

 

Will they rise that much in the MWM? The throat is much larger, so there isn't as much compression going on.

 

A K-43 has always been a drop-in for a K-33.  So its impedance in a horn would be about the same, 8 ohms nominal.  Two in parallel would be 4 ohms and you really should have a 4 ohm tap to run them. 

 

The impedance curve of the Jubilee is pretty typical.  Both of those woofers are 5.7 ohms Re (DCR). 

 

 

jubilee imp.pdf .pdf

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When I can get to the connections again (have to move some stuff around and climb over stuff), I'll hook the second woofer in each cabinet back up to the amp. Put the Duke in, instead of my 2A3 amps. I thought is wasn't turned on... so dang quiet. I can't hear my 2A3 amps from my listening position, but certainly can when my ear is up to the tweeters. This thing is quiet! NICE! Clean and tight bass!

 

Bruce

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Played Keith Urban's Drop Top, where he plays bass all the way though the song. Pretty unbelievable bass. The Crown D45 is doing a great job.

 

@dtel   Don't you use some smaller Crown amps on your system? Are your MWM singles wired in parallel?

 

Bruce

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5 hours ago, Marvel said:

 

@dtel   Don't you use some smaller Crown amps on your system? Are your MWM singles wired in parallel?

Had to go look, it's been 10 years since I connected them, yes they are in parallel.

 

I was using 2 Crown D 75's but one starting have a bad hiss, from the amp not the speaker. So just temporarily I tried 2 50 wpc amps and they sounded really good so I have not switched them. They sound as good as the 75's and dead quite, although I did like the blinky lights they had. :lol:

 

Emotiva mini x, I think they now call it the A 100 and they added an headphone jack to it, they are cheap $249 each.   

speakers.png

D1CF6682-B8FC-4A54-A92B-2A2568845DBE.jpeg

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8 hours ago, Marvel said:

Played Keith Urban's Drop Top, where he plays bass all the way though the song. Pretty unbelievable bass. The Crown D45 is doing a great job.

 

@dtel   Don't you use some smaller Crown amps on your system? Are your MWM singles wired in parallel?

 

Bruce

Single fold bass horns rule the audio world. You can get much deeper but you can't get better quality of sound.

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6 hours ago, dtel said:

Had to go look, it's been 10 years since I connected them, yes they are in parallel.

 

Thank you for the info. I knew they would sound great but the sound is so effortless.

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1 hour ago, Marvel said:

 

Thank you for the info. I knew they would sound great but the sound is so effortless.

Yes it is and it just sounds large. I kind of know what your hearing, I have some diy split LaScala tops with the same parts, and AA crossover but only one bin on each side and it sounds really good. Since I have it for outside and eventually for my workshop I get to turn it up and hear it outside at times, it's pretty impressive really. The Lascala top matches well and can easily keep up when played in a huge space. I have turned it up before and walked out into the yard hundreds of feet and it can fill acres with good sound even from a distance.

 

One strange thing I found was at 300 to 5oo feet when the wind blows it can move the sound waves away and you hear almost nothing, then it stops and it's back again. Now I am not talking about crazy power, this was with a HK 930 and not close to being over driven. 

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